My car is a 72 mach q-code (351-cj) The production date is 12/71 So it was built at the end of the 71 run going into 72....The date code on the bumper support /bumper mounting arms match the car's production date..I've owned it since 1979 & that is the way it came from the factory. It is a 4 speed .. competition susp ..deluxe interior car.
Scott,
Just happened across this post
I respectfully disagree, Mach 1's did not come with chrome bumpers.
Around 9 / 71 - 10 / 71 would be start of the new model year
At 12 / 71, I would say the last six of your vin is around 155,000
Car would have the 72 model year emissions but still some 71 items.
Probably has 71 non-sensor front seat belts and non retractable rear seat belts with no passenger side " fasten seat belt " light
Might still have 71 center seat back release latches on front seats.
It is possible the dealer changed the bumper.